12v battery dies repeatedly

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dcarleaf

Member
Joined
Mar 5, 2016
Messages
12
Four days ago I found my 2013 SL Leaf totally unresponsive. No lights (though the dome light came on once), nothing, and of course it wouldn't start. The dealer tested the 12v battery and found that it was not particularly low, but I replaced it anyway and the car worked fine for two days. Yesterday I didn't drive it at all, and it sat in the garage on the 220 charger. This morning the car is dead again. No dome lights, no dashboard readouts, doors don't lock or unlock. I've change the key fob batteries (last week), so it doesn't appear to be a key problem. There is nothing plugged in inside the car, the lights weren't left on. I'm stumped.
 
You could have a failing component that is keeping the car electronics active after it is turned off. Did they do a check for error codes when the battery was replaced?

Was the 12 volt battery fully charged when it was installed, or did you fully charge it at home after installation?

Do you have a bluetooth device plugged into the OBD port that is left connected?

Did you have the 3G radio upgrade done? Do you still have 2G service available?

Did it run a charge cycle during the time it was plugged in and sitting in the garage?
 
You either have a:
1) Charging system problem
2) Bad 12v battery

I once had a 2 "bad" 12v batteries in a row (defective replacement for my ICE car), so it's possible.
 
baustin said:
You could have a failing component that is keeping the car electronics active after it is turned off. Did they do a check for error codes when the battery was replaced?

Was the 12 volt battery fully charged when it was installed, or did you fully charge it at home after installation?

Do you have a bluetooth device plugged into the OBD port that is left connected?

Did you have the 3G radio upgrade done? Do you still have 2G service available?

Did it run a charge cycle during the time it was plugged in and sitting in the garage?

I had the 3G radio upgrade done on Wednesday; the 12v problem began Friday morning. Is there a possible connection. The battery was (supposedly) fully charged when installed. No Bluetooth device active (I turn the Bluetooth off on my phone when I'm not in the car). It did run a charge cycle while it was in the garage.
 
CORRECTION: Wednesday work was not the 3G radio one (that's a week or so from now) it was the airbag recall part and software update.
 
Any other changes to the car this week ?
New dongles or electronic gadgets, e.g ?

As posted above, either you have a (second) poor battery or something(s) are draining the 12v during the night.
Can you log energy drain through the OBDII port at a polling interval of say 5 minutes for a night ?
 
I will have to see if I can capture what might be draining it. I've had the car for three years and have not changed any routine that I know of. No new equipment in the garage or on the car; no. Ew Bluetooth devices in the house. This is a sudden and new development. The dealership is running tests and will check the battery again in case it's a dud. Thanks.
 
If the dealer checked the car, and it was unresponsive and there was an "ok" battery, then I think we are talking about a bad or faulty main power FUSE. I had a dead car when the main fuse went, but that was a gas powered car.. Just a shot....
 
How did you get the car to the dealer? Did you jump start it and drive it or have it towed? If you jump started and drove it, the battery would be somewhat recharged by driving so it would not be really low when tested at the dealer unless it was truly defective (bad cell, internal short circuit, etc.). Since the replacement battery was also found dead after being parked, something is discharging the battery.

Do you routinely leave the car plugged in in the garage after charging? There is more residual current drawn by the various modules in the car when it is plugged in and not actively charging than when it is not plugged in. I don't know if the 2013 will turn on the DC-DC converter to recharge the 12-volt battery while the car is plugged in or not (I know the 2011/2012 models will not so they will completely discharge the 12-volt battery if left plugged in, but am not sure about later models).

Until you find the cause, I recommend that you unplug Bluetooth dongles or other devices from the OBDII port when you park the car to eliminate the possibility that something is interfering with the car's "sleep" mode and keeping modules active. I had a small control relay fail to drop out once in a while on the 2011. It kept power to the shift control module so it would probably have discharged the battery if it had failed when I parked for longer than overnight.

Gerry
 
On Friday I had it jumped and then drove it there. Today we put it on a carrier and transported it there. I do leave it plugged in all night every night, but I've done that for three years without a problem. The dealership tells me the battery was still dead when the car arrived there so they're going to run diagnostics overnight to see if they can find out what is discharging it. If they find out I'll report it here. I appreciate all the feedback.
 
The dealer ran diagnostics overnight and found nothing drawing on the battery, and the car started fine this morning. Could this be simply a problem of leaving the car plugged into the charger all night, even after the charge is complete? I tend to do that in winter so I can run the heat in the morning while the car is still on the charger, and it has never been a problem before, but I'm wondering now if that's the cause (which of course I'll test).
 
Leaving the charging cable connected overnight should not be a problem unless the 12-volt battery is really weak. It will discharge the 12-volt battery a bit, but should not cause an issue unless it is plugged in for a longer period of time (perhaps 36 hours or longer).

Gerry
 
dcarleaf,

Ask your dealer for the actual 12v draw amount through the night. If it cannot be provided I would be skeptical that they know what they are talking about.
 
They were able to give me the draw, but they didn't find anything unusual. They ran diagnostics for two days and nights--on the charger and off. The car started for them every time. I'm at a loss at this point. I've ordered a portable battery jump starter and will try to continue diagnosing it on my own. I appreciate all the good suggestions y'all gave me. Thanks.
 
Disconnect OBD adapter if you have that.
Check battery terminals. They must be clean and not wiggling.
Get a hold of multimeter, open the hood and lock the car. Leave it to charge.
Check voltage every few hours. Write down.
Continue checking voltage after charge cycle ends.
Report.
 
Update on this situation: From January 5 until May 27, the Leaf ran as it always had--no dead 12v at any time. On May 27 in the afternoon, it's suddenly dead again. This time I had a battery pack that I used to jump it, but I would prefer not to do that too often. The only common denominator I can find among all the instances (though this may not be relevant) is that in every case (if I recall correctly), two or three days before the dead battery occurred, the car had been in the shop for some sort of maintenance and the 12v was disconnected during the maintenance. Why it would happen two or three days after that, I have no idea, so I suspect it's not the cause. I'm still stumped, though.
 
Each time you jump start the car from a dead battery, your actions after that (driving somewhere, or rather car in READY mode (green car w/arrows icon), charging via L1 or L2 EVSE may not be sufficient to charge up the 12 volt completely. After all, we already know the 12 volt charging algorithm on the Leaf is crap.

And, unfortunately, running a lead acid battery flat can be bad for it.

I'd suggest getting a 12 volt charger to separately charge up the 12 volt. I have one of the Tecmate Optimate 4's (https://tecmate.com/?post_type=products&productcategorie=battery-chargers). I have no idea what would happen if you charged on L1 and L2 while using this, so I'd recommend not doing that. I charge connected to the + post and have black connected to the black wire connection attached to the PDM stack, instead of the battery's negative post.
 
dcarleaf said:
...the car had been in the shop for some sort of maintenance and the 12v was disconnected during the maintenance. Why it would happen two or three days after that, I have no idea, so I suspect it's not the cause. I'm still stumped, though.

Because that's how long it took for what little charge was left in the battery (after they probably "topped it off") to drain. This happened to me when my battery pack was replaced. Bottom line: once a 12v battery is "drained" the damage is often irreparable.
 
I suggest that all leaf users with this concern get the following items... 1) a "Battery Tender" battery charger. It charges slowly, and you can leave it plugged into the 12v battery for months at a time because it is computer controlled. 2) Get a Harborfreight battery tester that you can do a "load test" on the battery to be assured that the battery has a good voltage, and then that the battery is good and can deliver when a heavy load is placed on it.. .. (Diagnostics 101).

I cannot imagine that the original poster put in a brand new, fully charged battery, and the battery was dead in only 1 day. If that is true, then you can test with an ammeter to see how much current is being drawn from the battery when the car is completely "off". This issue is a common one with cars, and should not be a "murder mystery"..... good luck...
 
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